This invention relates to an arrangement for the cooling of thermally highly loaded components by means of a cooling medium, and in particular, the cooling of the combustion chamber of gas turbines, in which cooling air openings are provided in the component to be cooled which are supplied with cooling air at an air inlet side to form a cooling air film at the air outlet side of the component.
As is generally known, various components of a gas turbine, for example, the stator vanes and their platforms or the combustion chamber, are cooled with a multitude of minute cooling air openings or slots provided in the wall area, each with a cross-sectional area of approximately 1 mm2, for example. The cooling air which is externally applied to the outer surface of the component also passes the respective wall area of the component via this multitude of cooling air openings to produce a cooling air film on the inner surface of the wall, thus directly shielding the wall against the hot combustion gases and keeping it below a temperature corresponding to the maximum thermal loadability of the respective component material.
The combustion chambers of aircraft engines include, as is generally known, individual rings which are made by non-cutting or cutting forming processes and joined by welding. The circumferential steps of a Z-shaped combustion chamber wall and the respective heat shield in the area of the burners contain several thousand minute cooling air openings which are produced by laser drilling. However, the effort for the laser drilling of the cooling air openings is largely uneconomical in relation to the total costs for the manufacture of the combustion chamber.
As is already known, combustion chambers for aircraft turbine engines are also made from individual segments produced by a casting process and joined by laser welding, but here as well, the fine cooling air openings must be expensively produced by lasering since it is impossible to incorporate their production even into the most advanced precision casting process.